document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=697434>Question 697434</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A laptop computer is purchased for $1200 . Each year, its value is 70% of its value the year before. After how many years will the laptop computer be worth $300  or less?  \r<BR>\n" );
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document.write( "Write the answer as a whole number.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #429991 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=429991\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> For now, let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+p+ ALIGN=MIDDLE  ALT=\"+p+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the purchase price<BR>\n" );
document.write( "The value is:<BR>\n" );
document.write( "1st yr: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+p+ ALIGN=MIDDLE  ALT=\"+p+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "2nd yr: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+.7p+ ALIGN=MIDDLE  ALT=\"+.7p+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "3rd yr: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+.7%2A%28+.7p+%29+ ALIGN=MIDDLE  ALT=\"+.7%2A%28+.7p+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "4th yr: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+.7%5E3%2Ap+ ALIGN=MIDDLE  ALT=\"+.7%5E3%2Ap+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "etc<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+V+ ALIGN=MIDDLE  ALT=\"+V+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the current value of the laptop<BR>\n" );
document.write( "------------------<BR>\n" );
document.write( "If <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n+ ALIGN=MIDDLE  ALT=\"+n+\"   DISABLED_style= \"max-width:90%; height:auto;\" > the number of years,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+V+=+.7%5E%28n+-+1%29%2Ap+ ALIGN=MIDDLE  ALT=\"+V+=+.7%5E%28n+-+1%29%2Ap+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "( I use the <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n-1+ ALIGN=MIDDLE  ALT=\"+n-1+\"   DISABLED_style= \"max-width:90%; height:auto;\" > because it makes the <BR>\n" );
document.write( "1st year <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+.7%5E%28+1-1%29%2Ap+=+p+ ALIGN=MIDDLE  ALT=\"+.7%5E%28+1-1%29%2Ap+=+p+\"   DISABLED_style= \"max-width:90%; height:auto;\" > )<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+p+=+1200+ ALIGN=MIDDLE  ALT=\"+p+=+1200+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+V+=+300+ ALIGN=MIDDLE  ALT=\"+V+=+300+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+300+=+.7%5E%28+n-1+%29%2A1200+ ALIGN=MIDDLE  ALT=\"+300+=+.7%5E%28+n-1+%29%2A1200+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+.7%5E%28+n-1+%29+=+1%2F4+ ALIGN=MIDDLE  ALT=\"+.7%5E%28+n-1+%29+=+1%2F4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+.7%5E%28+n-1+%29+=+.25+ ALIGN=MIDDLE  ALT=\"+.7%5E%28+n-1+%29+=+.25+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Take the log base 10 of both sides<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+log%28+.7%5E%28+n-1+%29+%29+=+log%28+.25+%29+ ALIGN=MIDDLE  ALT=\"+log%28+.7%5E%28+n-1+%29+%29+=+log%28+.25+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28+n-1+%29%2Alog%28+.7+%29+=+log%28+.25+%29+ ALIGN=MIDDLE  ALT=\"+%28+n-1+%29%2Alog%28+.7+%29+=+log%28+.25+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n-1+=+log%28+.25+%29+%2F+log%28+.7+%29+ ALIGN=MIDDLE  ALT=\"+n-1+=+log%28+.25+%29+%2F+log%28+.7+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n+=++log%28+.25+%29+%2F+log%28+.7+%29+%2B+1+ ALIGN=MIDDLE  ALT=\"+n+=++log%28+.25+%29+%2F+log%28+.7+%29+%2B+1+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n+=+%28+-.60206+%29+%2F+%28+-.1549+%29+%2B+1+ ALIGN=MIDDLE  ALT=\"+n+=+%28+-.60206+%29+%2F+%28+-.1549+%29+%2B+1+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n+=+3.8868+%2B+1+ ALIGN=MIDDLE  ALT=\"+n+=+3.8868+%2B+1+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n+=+4.8868+ ALIGN=MIDDLE  ALT=\"+n+=+4.8868+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "After the 4th year, the laptop will be<BR>\n" );
document.write( "worth $300 or less.<BR>\n" );
document.write( "----------------<BR>\n" );
document.write( "Check answer:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+V+=+.7%5E%28+n-1+%29%2A1200+ ALIGN=MIDDLE  ALT=\"+V+=+.7%5E%28+n-1+%29%2A1200+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+V+=+.7%5E%284.8868-1%29%2A1200+ ALIGN=MIDDLE  ALT=\"+V+=+.7%5E%284.8868-1%29%2A1200+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+V+=+.7%5E3.8868%2A1200+ ALIGN=MIDDLE  ALT=\"+V+=+.7%5E3.8868%2A1200+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+V+=+.24999%2A1200+ ALIGN=MIDDLE  ALT=\"+V+=+.24999%2A1200+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+V+=+300+ ALIGN=MIDDLE  ALT=\"+V+=+300+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );